#[no_mangle]
pub extern "C" fn add(left: usize, right: usize) -> usize {
    println!("{}+{}...", left, right);
    left + right
}

#[no_mangle]
pub extern "C" fn say_hello() -> u32 {
    println!("I just want to say hello.");
    5
}

#[no_mangle]
pub extern "C" fn say_hello_without_ret() {
    println!("I just want to say hello1111.");
}

pub fn my_add(a1:u32, a2:u32)->u32{
    a1+a2
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn it_works() {
        let result = add(2, 2);
        assert_eq!(result, 4);
    }
}
